Umbrella Group
A set of largely non-European developed countries who occasionally act as a
negotiating bloc on specific issues.

United Nations Framework Convention on Climate Change (UNFCCC)
The Convention was adopted on 9 May 1992 in New York and signed at the 1992
Earth Summit in Rio de Janeiro by more than 150 countries and the European Economic
Community. Its ultimate objective is the stabilization of greenhouse gas
concentrations in the atmosphere at a level that would prevent dangerous anthropogenic
interference with the climate system. It contains commitments for all
Parties. Under the Convention Parties included in Annex I aim
to return greenhouse gas emission not controlled by the Montreal Protocol
to 1990 levels by the year 2000. The Convention entered in force in March 1994.
See also Conference of the Parties and Kyoto Protocol.

Uncertainty
An expression of the degree to which a value (e.g., the future state of the
climate system) is unknown. Uncertainty can result from lack of information
or from disagreement about what is known or even knowable. It may have many
types of sources, from quantifiable errors in the data to ambiguously defined
concepts or terminology, or uncertain projections of human behaviour. Uncertainty
can therefore be represented by quantitative measures (e.g., a range of values
calculated by various models) or by qualitative statements (e.g., reflecting
the judgement of a team of experts).